Electrophysiological evaluation in normal-tension glaucoma suspects: a pilot study

Purpose: To evaluate the variations of intraocular pressure (IOP), morphometric papillary characteristics, perimetric indices and electrophysiological parameters (Pattern electroretinogram and visual evoked potentials) before and after topic hypotonization therapy in patients with suspect normal tension glaucoma.Methods: we evaluated 38 eyes of 20 patients with intraocular pressure < 21 mmHg (measured with Goldman applanation tonometry), initial glaucomatous optic neuropathy (valued with HRT: retinal fiber layer (RNFL) and/or linear cup/disk (linear C/D), minimal visual defects (Octopus 101: G2 program), visual acuity more than 15/20 with best correction and pathological electrophysiological parameters (valued with pattern electroretinogram and visual evoked potentials), free of systemic or other ocular diseases. All parameters were evaluated at the beginning of the study (T0) and after 12 months from the beginning of the therapy (T12). A randomized normal control group (27 eyes of 14 subjects) with apparent larger disc cupping underwent all exams at initial of study and after 12 months. Results:At T0, P100 Latency VEPs in LTG was slightly increased either at 15’ (12,9 msec) and 30’ (8,9 msec). At T0, P100 Amplitude VEPs in LTG group were reduced compared to normal subjects, with average differences of: -6.4 µV (95% C.I.: (-9.8, -3.0) µV) for 15'; and: -5.4 µV (95% C.I.: ( -8.9, -2.0) µV) for 30’. P50N95 complex amplitude PERG was reduced at T0 in LTG, with average differences: -0.9 (95% C.I.: ( -1.4, -0.4) µV), -0.8 (-1.3, -0.3) µV) for 15’ and 30’, respectively; than it improved after therapy, with average differences between T12 and T0 of 0.3 µV (95% C.I.: (0.1, 0.6) µV) and 0.5 µV (95% C.I.: ( 0.2, 0.8) µV). So IOP decreased at T12 in LTG group, with an average difference between T12 and T0 of -5.2 mmHg (95% C.I.: (-5.9, -4.4). mmHg). Finally, CRT was slight delayed in LTG group at T0. Conclusion: In a viewpoint of an integrated diagnostic, electrophysiological tests (VEPs and PERG) could provide a more sensitive measure of retinal ganglion cell integrity and help to distinguish between suspect normal-pressure glaucoma patients before perimetric alterations are evident and normal subjects with apparent larger disc cupping.

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Integrated electrophysiological evaluation in early normal-tension glaucoma

Modeling and Artificial Intelligence in Ophthalmology ◽

10.35119/maio.v1i2.34 ◽

2016 ◽

Vol 1 (2) ◽

pp. 79-88

Author(s):

Dario Messenio ◽

Giuseppe Marano ◽

Elia Biganzoli

Keyword(s):

Optic Nerve ◽

Visual Field ◽

Evoked Potentials ◽

Visual Evoked Potentials ◽

Optic Nerve Head ◽

Pattern Electroretinogram ◽

Normal Subjects ◽

Visual Field Defects ◽

Control Group ◽

Visual Evoked

Purpose: To evaluate the variations of intraocular pressure (IOP), morphometric optic nerve head characteristic, perimetric indices and electrophysiological parameters (pattern electroretinogram and visual evoked potentials) before and after topical IOP lowering in patients with early normal-tension glaucoma.Methods: we evaluated 38 eyes of 20 patients with IOP < 21 mmHg, initial glaucomatous optic neuropathy (valued with HRT: retinal nerve fiber layer thickness (RNFL) and linear cup/disk ratio (linear C/D ratio)), minimal visual field defects (Octopus 101: G2 program), best correct visual acuity more than 15/20 and pathological electrophysiological parameters (valued with pattern electroretinogram (PERG) and visual evoked potentials (VEPs)), free of systemic or other ocular diseases. All parameters were evaluated at the beginning of the study (T0) and after 12 months of therapy (T12). A randomized normal control group (27 eyes of 14 subjects) with apparent larger disc cupping underwent all exams at initial of study (T0) and after 12 months (T12).Results: Among electrophysiological parameters, at the beginning of the study NTG P100 VEPs latency is slightly increased and P100 amplitude is reduced compared to normal subjects. There are not significant variations after 12 months. P50 PERG latency in NTG is quite similar respect normal and do not modify after therapy. P50N95 complex PERG amplitude in NTG is reduced compared to normal subjects and slightly increases after 12 months (1.8 vs 1.5 ; 2.4 vs 1.9 micronvolts, with different checkboard spatial frequency). Cortical retinal time (CRT) is slightly delayed in NTG and does not modify. Among visual field indices, MD and CLV is slightly higher in NTG and do not significantly modify after therapy. Among morphometric optic nerve head characteristics, linear C/D and RNFL thickness are quite similar in NTG and do not modify. IOP is quite similar between NTG and control group and modifies in NTG after therapy.Conclusion: In a viewpoint of an integrated diagnostic, electrophysiological tests (VEPs and PERG) could provide a more sensitive measure of retinal ganglion cell integrity and help to distinguish between early normal-pressure glaucoma patients with no or minimal visual field alterations and normal subjects with apparent larger disc cupping.

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Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

Methods of Information in Medicine ◽

10.1055/s-0038-1636871 ◽

1997 ◽

Vol 36 (04/05) ◽

pp. 315-318 ◽

Cited By ~ 3

Author(s):

K. Momose ◽

K. Komiya ◽

A. Uchiyama

Keyword(s):

Visual System ◽

Evoked Potentials ◽

Visual Evoked Potentials ◽

Normal Subjects ◽

Second Order ◽

First Order ◽

The Relationship ◽

Perceived Color ◽

Second Order Nonlinearity ◽

Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

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Effect of levodopa on the human pattern electroretinogram and pattern visual evoked potentials

Graefe s Archive for Clinical and Experimental Ophthalmology ◽

10.1007/bf02172892 ◽

1989 ◽

Vol 227 (5) ◽

pp. 421-427 ◽

Cited By ~ 27

Author(s):

Irene Gottlob ◽

Herbert Weghaupt ◽

Clemens Vass ◽

Eduard Auff

Keyword(s):

Evoked Potentials ◽

Visual Evoked Potentials ◽

Pattern Electroretinogram ◽

Pattern Visual Evoked Potentials ◽

Visual Evoked

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Bilateral Glaucomatous Optic Neuropathy Caused by Eye Rubbing

Case Reports in Ophthalmology ◽

10.1159/000439163 ◽

2015 ◽

Vol 6 (3) ◽

pp. 279-283 ◽

Cited By ~ 1

Author(s):

Alfonso Savastano ◽

Maria Cristina Savastano ◽

Laura Carlomusto ◽

Silvio Savastano

Keyword(s):

Intraocular Pressure ◽

Visual Field ◽

Optic Disc ◽

Optic Neuropathy ◽

Correct Diagnosis ◽

Visual Fields ◽

Pattern Electroretinogram ◽

Glaucomatous Optic Neuropathy ◽

Fiber Layer ◽

The Right

In this report, we describe a particular condition of a 52-year-old man who showed advanced bilateral glaucomatous-like optic disc damage, even though the intraocular pressure resulted normal during all examinations performed. Visual field test, steady-state pattern electroretinogram, retinal nerve fiber layer and retinal tomographic evaluations were performed to evaluate the optic disc damage. Over a 4-year observational period, his visual acuity decreased to 12/20 in the right eye and counting fingers in the left eye. Visual fields were severely compromised, and intraocular pressure values were not superior to 14 mm Hg during routine examinations. An accurate anamnesis and the suspicion of this disease represent a crucial aspect to establish the correct diagnosis. In fact, our patient strongly rubbed his eyes for more than 10 h per day. Recurrent and continuous eye rubbing can induce progressive optic neuropathy, causing severe visual field damage similar to the pathology of advanced glaucoma.

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Cortical Contrast Processing in Retinitis Pigmentosa: Evidence of PVEPs Spatial Functions

European Journal of Investigation in Health, Psychology and Education ◽

10.3390/ejihpe10040071 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1010-1019

Author(s):

Rafael Mancebo-Azor ◽

José Antonio Sáez-Moreno ◽

José Manuel Rodríguez-Ferrer

Keyword(s):

Retinitis Pigmentosa ◽

Evoked Potentials ◽

Visual Evoked Potentials ◽

Normal Subjects ◽

Pattern Reversal ◽

Check Size ◽

Low Contrast ◽

Control Subjects ◽

The Right ◽

Visual Evoked

Objective: To study the effect of check width size of the stimuli on the amplitude and latency of the P100 component of visual evoked potentials recorded in patients with retinitis pigmentosa (RP). Methods: Pattern reversal visual evoked potentials (PVEPs) were recorded in 16 RP patients and 20 visually normal subjects. Pattern reversal stimuli with five different check widths and 100% of contrast were projected in the right eye of both patients and control subjects. PVEPs induced by stimuli with 78%, 16%, and 6% of contrast were also recorded in 10 of the control subjects. Results: In RP patients, the amplitude of P100 was smaller than controls in all check sized used and the peak P100 amplitude was obtained with a larger check width than in controls. P100 was also delayed in RP patients in all check sizes studied. The P100 amplitude- and latency-check size functions of RP patients were like those found in control subjects with low contrast stimuli of 16% and 6%. Conclusion: The PVEPs spatial functions of RP patients show quantitative and qualitative changes, suggesting disease induced alteration in the neural processing of stimulus contrast.

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Multifocal visual-evoked potentials in patients with schizophrenia during treatment

Acta Neuropsychiatrica ◽

10.1111/j.1601-5215.2010.00509.x ◽

2011 ◽

Vol 23 (1) ◽

pp. 31-34 ◽

Cited By ~ 4

Author(s):

Mariko Yamada ◽

Eiichi Yukawa ◽

Futoshi Taketani ◽

Toyoaki Matsuura ◽

Yoshiaki Hara

Keyword(s):

Evoked Potentials ◽

Visual Evoked Potentials ◽

Normal Subjects ◽

Subject Group ◽

Recording Apparatus ◽

Multifocal Visual Evoked Potentials ◽

Psychotropic Agents ◽

Schizophrenic Patients ◽

Conventional Perimetry ◽

Visual Evoked

Aim: Investigation of responses of multifocal visual-evoked potentials (mfVEPs) in schizophrenic patients under treatment in whom no abnormality was detected on the conventional perimetry.Methods: Recordings of mfVEPs were performed in 31 schizophrenic patients and 30 normal subjects using a VERIS Junior Science recording apparatus (Mayo, Aichi, Japan). Responses from eight sites in each subject were divided into four quadrants (superior and inferior temporal quadrants, and superior and inferior nasal quadrants). In each quadrant, two response waves were grouped and averaged, and the latency and amplitude of main waveforms that appeared near 100 ms were evaluated.Results: The peak latency was about 7–9 ms prolonged and the amplitude was reduced by about 2–5 nV/deg2 in the schizophrenic patient group compared to those in the normal subject group, and significant differences were noted in both parameters in all quadrants.Conclusion: In schizophrenic patients under treatment with psychotropic agents, prolongation of the latency and amplitude reduction were noted in mfVEPs even though no abnormality was detected on the conventional perimetry.

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The effect of ingested sulfite on visual evoked potentials, lipid peroxidation, and antioxidant status of brain in normal and sulfite oxidase-deficient aged rats

Toxicology and Industrial Health ◽

10.1177/0748233714552688 ◽

2014 ◽

Vol 32 (7) ◽

pp. 1197-1207 ◽

Cited By ~ 5

Author(s):

Ozlem Ozsoy ◽

Sinem Aras ◽

Ayse Ozkan ◽

Hande Parlak ◽

Mutay Aslan ◽

...

Keyword(s):

Evoked Potentials ◽

Visual Evoked Potentials ◽

Thiobarbituric Acid ◽

Sulfite Oxidase ◽

Activity Level ◽

Control Group ◽

Sodium Metabisulfite ◽

Aged Rats ◽

Significant Difference ◽

Visual Evoked

Sulfite, commonly used as a preservative in foods, beverages, and pharmaceuticals, is a very reactive and potentially toxic molecule which is detoxified by sulfite oxidase (SOX). Changes induced by aging may be exacerbated by exogenous chemicals like sulfite. The aim of this study was to investigate the effects of ingested sulfite on visual evoked potentials (VEPs) and brain antioxidant statuses by measuring superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities. Brain lipid oxidation status was also determined via thiobarbituric acid reactive substances (TBARS) in normal- and SOX-deficient aged rats. Rats do not mimic the sulfite responses seen in humans because of their relatively high SOX activity level. Therefore this study used SOX-deficient rats since they are more appropriate models for studying sulfite toxicity. Forty male Wistar rats aged 24 months were randomly assigned to four groups: control (C), sulfite (S), SOX-deficient (D) and SOX-deficient + sulfite (DS). SOX deficiency was established by feeding rats with low molybdenum (Mo) diet and adding 200 ppm tungsten (W) to their drinking water. Sulfite in the form of sodium metabisulfite (25 mg kg−1 day−1) was given by gavage. Treatment continued for 6 weeks. At the end of the experimental period, flash VEPs were recorded. Hepatic SOX activity was measured to confirm SOX deficiency. SOX-deficient rats had an approximately 10-fold decrease in hepatic SOX activity compared with the normal rats. The activity of SOX in deficient rats was thus in the range of humans. There was no significant difference between control and treated groups in either latence or amplitude of VEP components. Brain SOD, CAT, and GPx activities and brain TBARS levels were similar in all experimental groups compared with the control group. Our results indicate that exogenous administration of sulfite does not affect VEP components and the antioxidant/oxidant status of aged rat brains.

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